2100 Bioanalyzer, strange sharp peak in precursor region

[vtorda]

Hi All!
I usually get a sharp peak in the precursor region, and I don’t know what can cause this anomaly!?
Details:
I extracted RNA from cryo-sections from fungal fruiting body by PicoPure RNA isolation Kit applying DNase treatment. The samples were fixed in Farmer’s fixative (Abs. alcohol and glacial acetic acid) and then were impregnated by sucrose solution. After this, the samples were embedded in OCT. The sections were on PEN membrane covered slide and were cut by a Gillette blade into a Lobind tube containing PicoPure extraction buffer.
I suspect that the problem is not with the samples, because I always load a control sample on the chip, which, if I remember well, is a human RNA extraction.
Dirty electrodes can cause these peak? Or what do you think?
Thank you very much!

[vtorda]

Hi all,

I have figured it out! I usually did electrode decontamination using RNaseZAP. I filled the wells of the electrode cleaner with ZAP, and then I put it in the instrument for 30 sec. After this I washed the electrodes by RNase-free water using an other electrode cleaner. In this case I constantly experienced that high peak, but since I haven’t been doing the decontamination step, the high peaks disappeared!

[MisUser]

We experienced the same issue, until we diluted the RNAZap at 1:2 then the problem was solved.

[vtorda]

Thank you the advice, I will try it!